This invention relates to an apparatus for storing input pens for writing letters and/or graphic patterns on a board having a tabulation function.
Recently, so-called tele-conference systems have been put into practical use. In these systems, an electronic input board having a tabulation function (hereinafter referred to as an electronic board) is usually installed at each local site. By use of such electronic boards, conference attendees at remote locations can confer with each other by way of timely hand-written information such as that used in a conference room (e.g., on a blackboard, overhead projector, etc.). Such electronic tabulation boards have been offered under the trademark "GEMINI 100 Electronic Blackboard" sold by AT&T or the trademark "FACOM 2260 OA Board System" sold by Fujitsu, for example.
The principle function of the electronic board is to detect the positional coordinate of a hand-held input instrument, such as a piece of chalk, a pencil or some other special input instrument, when the input instrument contacts the surface of an input board. The coordinates of the contact points are stored or transmitted to a display unit, and the reproduction of the contact points (which form letters or graphic patterns) is displayed on the display unit.
Generally, electronic board systems can be classified into two types, in accordance with the method by which the coordinates of the contact points are detected. One type is a pressure sensing type which detects the contact between a hand-held instrument and an input board by using a pressure sensitive tablet board as the input board. The other type is a magnetic type, wherein the coordinates of the contact points are magnetically detected.
The magnetic type system includes two subtypes: a first in which the electronic board detects signals generated by a hand-held input pen; and a second in which the electronic board generates signals and the hand-held input pen detects the signals.
The essential part of a magnetic type electronic board of the second subtype is illustrated in FIG. 1. The input board includes an electronic board 1 (tabulator of patterns written on the input board) having installed therein a number of coils arranged in the X and Y directions, with the distance between the coils depending upon the desired resolution. The coils are usually fabricated by employing a technology similar to that for fabricating printed circuit boards. The coils include X-coils 2 and Y-coils 3 in accordance with the direction in which the coils are arranged, as shown in FIG. 1. The X-coils 2 and Y-coils 3 are excited individually with electric current, so that the magnetic field generated by the coils varies in dependence upon the position (in the X and Y directions) on the board 1. When a letter 6 (for example "A") is written on the board 1 by use of an input pen 5, a detection coil 4 installed in the input pen 5 detects the magnetic field at the surface of the board 1. Based on the timing or phase of the magnetic field detected by the coil 4, the positional coordinate of input pen 5 on the board 1 is detected. Thus, data representing the letter 6 is input into the system and a corresponding letter 6 is reproduced on a display unit 7 which is installed at a local or remote site.
Color information can also be processed by the electronic board. An example of one color information input system is disclosed in U.S. patent application Ser. No. 507,497, filed June 24, 1983 titled "Color Information Input System for Electronic Board" and assigned to the assignee of the subject application, the disclosure of which is hereby incorporated by reference. In that system, multiple color information is input by using a single input pen consisting of a pen holder and a selected one of plural color felt pens which are replaceably mounted in the pen holder.
FIGS. 2A and 2B are illustrations of a prior art pen holder 8 and a prior art felt pen 15, respectively. Referring to FIG. 2A, the pen holder 8 includes an outer tube 9 made of, for example, a synthetic resin, an inner tube 10 positioned within the outer tube 9, and a detection coil 11 which is coaxially wound around the bottom end region of the inner tube 10. The pen holder 8 further includes a chuck 12 having a tapered hole 12a, the open end of which is directed downward and which is positioned adjacent the upper end portion in the inner tube 10. The chuck 12 is positioned so as to be able to move slightly (about 1 to 2 millimeters, for instance) in its axial direction and is biased in a downward position by spiral spring 13, so that the chuck 12 is normally located at its lowest limit position. A switch (e.g., switch 30 in FIG. 2C) is installed above the chuck 12, so that the switch changes to an ON state when the chuck 12 is pressed upward to reach its upper limit position. The switch is connected to a cord 14 which extends through the upper end of the holder 8.
In FIG. 2B, the felt pen 15, which is to be mounted in the pen holder 8 (FIG. 2A), includes a casing 16 which is adaptable to be removably inserted inside the inner tube 10 of FIG. 2A. The felt pen 15 further includes a filler 17 which is, for example, cotton (and which is soaked with ink), and a felt stick 18 mounted in a hole formed in a neck 16a of the casing 16. Ink soaked up by the filler 17 penetrates the felt stick 18, and reaches an exposed tip 18a of the felt stick 18. At the top end of the casing 16, a casing-head 19 is attached, and the upper portion 19a of the casing-head 19 is tapered to fit within the chuck 12 of the holder 8 (FIG. 2A). When a felt pen filled with ink of a desired color is selected and inserted into the pen holder 8 of FIG. 2A, the casing-head 19 is pushed into the tapered hole 12a and is held by the chuck 12. In this manner, the felt pen 15 is secured in the pen holder.
When the felt pen 15 is used to write a letter or graphic pattern on the electronic board 1, the tip 18a is pressed onto the surface of the board 1, and the felt pen 15 is displaced upwardly in the pen holder 8. As a result, the switch installed in the pen holder 8 is turned on, and positional coordinate signals detected by detection coil 11 are sent to the display unit 7. Referring to FIG. 2C, the switch may include a reed switch 30, (i.e., a magnetically activated switch) secured to the top of the inner tube 10, and a magnetic element 31 secured to the top of chuck 12. When the felt pen 15 is displaced upwardly, the reed switch 30 is activated by the approach of the magnetic element 31.
The felt pens which are not in use (unused felt pens) are stored in an apparatus equipped with caps, and the point of each unused felt pen is inserted in the cap to prevent evaporation of the ink. The caps also help to prevent inadvertent stray marking of fingers, clothes, walls, etc.
This prior art configuration of the input pen, including a demountable felt pen 15, provides advantages in avoiding an increase in system costs and inconvenience due to entangling of cords, both of which will occur if multiple input pens (including multiple pen holders 8) are used.